package com.anclick.englishword;

import android.graphics.Camera;
import android.graphics.Matrix;
import android.view.animation.Animation;
import android.view.animation.Transformation;


public class Rotate3dAnimation extends Animation {
	  private final float mFromDegrees;
	  private final float mToDegrees;
	  private final float mCenterX;
	  private final float mCenterY;
	  private final float mDepthZ;
	  private final boolean mReverse;
	  private Camera mCamera;

	  /**
	   * Creates a new 3D rotation on the Y axis. The rotation is defined by its
	   * start angle and its end angle. Both angles are in degrees. The rotation
	   * is performed around a center point on the 2D space, definied by a pair of
	   * X and Y coordinates, called centerX and centerY. When the animation
	   * starts, a translation on the Z axis (depth) is performed. The length of
	   * the translation can be specified, as well as whether the translation
	   * should be reversed in time.
	   * 
	   * @param fromDegrees
	   *            the start angle of the 3D rotation
	   * @param toDegrees
	   *            the end angle of the 3D rotation
	   * @param centerX
	   *            the X center of the 3D rotation
	   * @param centerY
	   *            the Y center of the 3D rotation
	   * @param reverse
	   *            true if the translation should be reversed, false otherwise
	   */
	  public Rotate3dAnimation(float fromDegrees, float toDegrees, float centerX,
	      float centerY, float depthZ, boolean reverse) {
	    mFromDegrees = fromDegrees;
	    mToDegrees = toDegrees;
	    mCenterX = centerX;
	    mCenterY = centerY;
	    mDepthZ = depthZ;
	    mReverse = reverse;
	  }

	  @Override
	  public void initialize(int width, int height, int parentWidth,
	      int parentHeight) {
	    super.initialize(width, height, parentWidth, parentHeight);
	    mCamera = new Camera();
	  }

	  @Override
	  protected void applyTransformation(float interpolatedTime, Transformation t) {
	    final float fromDegrees = mFromDegrees;
	    float degrees = fromDegrees
	    + ((mToDegrees - fromDegrees) * interpolatedTime);

	    final float centerX = mCenterX;
	    final float centerY = mCenterY;
	    final Camera camera = mCamera;

	    final Matrix matrix = t.getMatrix();

	    camera.save();
	    if (mReverse) {
	      camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);
	    } else {
	      camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));
	    }
	    camera.rotateY(degrees);
	    camera.getMatrix(matrix);
	    camera.restore();

	    matrix.preTranslate(-centerX, -centerY);
	    matrix.postTranslate(centerX, centerY);

	  }
	}
